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daemon: use fee rates rather than absolute fees (BOLT ElementsProject#2)
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And divide fees as specified there.

We still use fixed values rather than floating, and we don't send or
handle update_fee messages.

Signed-off-by: Rusty Russell <[email protected]>
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@rustyrussell
rustyrussell committed Mar 24, 2016
1 parent ba2854e commit 8c468c1
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Showing 11 changed files with 497 additions and 330 deletions.
60 changes: 29 additions & 31 deletions daemon/lightningd.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -82,15 +82,15 @@ static void config_register_opts(struct lightningd_state *dstate)
opt_register_arg("--forever-confirms", opt_set_u32, opt_show_u32,
&dstate->config.forever_confirms,
"Confirmations after which we consider a reorg impossible");
opt_register_arg("--commit-fee", opt_set_u64, opt_show_u64,
&dstate->config.commitment_fee,
"Satoshis to offer for commitment transaction fee");
opt_register_arg("--min-commit-fee", opt_set_u64, opt_show_u64,
&dstate->config.commitment_fee_min,
"Minimum satoshis to accept for commitment transaction fee");
opt_register_arg("--closing-fee", opt_set_u64, opt_show_u64,
&dstate->config.closing_fee,
"Satoshis to use for mutual close transaction fee");
opt_register_arg("--commit-fee-rate", opt_set_u64, opt_show_u64,
&dstate->config.commitment_fee_rate,
"Satoshis to offer for commitment transaction fee (per kb)");
opt_register_arg("--min-commit-fee-rate", opt_set_u64, opt_show_u64,
&dstate->config.commitment_fee_rate_min,
"Minimum satoshis to accept for commitment transaction fee (per kb)");
opt_register_arg("--closing-fee-rate", opt_set_u64, opt_show_u64,
&dstate->config.closing_fee_rate,
"Satoshis to use for mutual close transaction fee (per kb)");
opt_register_arg("--min-expiry", opt_set_u32, opt_show_u32,
&dstate->config.min_expiry,
"Minimum number of seconds to accept an HTLC before expiry");
Expand Down Expand Up @@ -128,14 +128,14 @@ static void default_config(struct config *config)

/* FIXME: These should float with bitcoind's recommendations! */

/* Pay hefty fee (10x current suggested minimum). */
config->commitment_fee = 50000;
/* Pay hefty fee (double historic high of ~100k). */
config->commitment_fee_rate = 200000;

/* Don't accept less than double the current standard fee. */
config->commitment_fee_min = 10000;
/* Don't accept less than double the average 2-block fee. */
config->commitment_fee_rate_min = 50000;

/* Use this for mutual close. */
config->closing_fee = 10000;
config->closing_fee_rate = 20000;

/* Don't bother me unless I have 6 hours to collect. */
config->min_expiry = 6 * HOURS;
Expand All @@ -149,24 +149,22 @@ static void check_config(struct lightningd_state *dstate)
{
/* BOLT #2:
* The sender MUST set `close_fee` lower than or equal to the
* fee of the final commitment transaction, and MUST set
* `close_fee` to an even number of satoshis.
* fee of the final commitment transaction.
*/
if (dstate->config.closing_fee > dstate->config.commitment_fee)
fatal("Closing fee %"PRIu64
" can't exceed commitment fee %"PRIu64,
dstate->config.closing_fee,
dstate->config.commitment_fee);

if (dstate->config.closing_fee & 1)
fatal("Closing fee %"PRIu64 "must be even.",
dstate->config.closing_fee);

if (dstate->config.commitment_fee_min > dstate->config.commitment_fee)
fatal("Minumum fee %"PRIu64
" can't exceed commitment fee %"PRIu64,
dstate->config.commitment_fee_min,
dstate->config.commitment_fee);

/* We do this by ensuring it's less than the minimum we would accept. */
if (dstate->config.closing_fee_rate > dstate->config.commitment_fee_rate_min)
fatal("Closing fee rate %"PRIu64
" can't exceed minimum commitment fee rate %"PRIu64,
dstate->config.closing_fee_rate,
dstate->config.commitment_fee_rate_min);

if (dstate->config.commitment_fee_rate_min
> dstate->config.commitment_fee_rate)
fatal("Minumum fee rate %"PRIu64
" can't exceed commitment fee rate %"PRIu64,
dstate->config.commitment_fee_rate_min,
dstate->config.commitment_fee_rate);
}

static struct lightningd_state *lightningd_state(void)
Expand Down
10 changes: 5 additions & 5 deletions daemon/lightningd.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -29,14 +29,14 @@ struct config {
/* How many blocks until we stop watching a close commit? */
u32 forever_confirms;

/* What are we prepared to pay in commitment fee (satoshis). */
u64 commitment_fee;
/* What are we prepared to pay in commitment fee (satoshis/kb). */
u64 commitment_fee_rate;

/* How little are we prepared to have them pay? */
u64 commitment_fee_min;
u64 commitment_fee_rate_min;

/* What fee we use for the closing transaction (satoshis) */
u64 closing_fee;
/* What fee we use for the closing transaction (satoshis/kb) */
u64 closing_fee_rate;

/* Minimum/maximum time for an expiring HTLC (seconds). */
u32 min_expiry, max_expiry;
Expand Down
64 changes: 21 additions & 43 deletions daemon/packets.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -81,7 +81,7 @@ Pkt *pkt_open(const tal_t *ctx, const struct peer *peer,
locktime__init(o->delay);
o->delay->locktime_case = LOCKTIME__LOCKTIME_SECONDS;
o->delay->seconds = rel_locktime_to_seconds(&peer->us.locktime);
o->commitment_fee = peer->us.commit_fee;
o->initial_fee_rate = peer->us.commit_fee_rate;
if (anchor == OPEN_CHANNEL__ANCHOR_OFFER__WILL_CREATE_ANCHOR)
assert(peer->us.offer_anchor == CMD_OPEN_WITH_ANCHOR);
else {
Expand Down Expand Up @@ -289,8 +289,8 @@ Pkt *accept_pkt_open(const tal_t *ctx,
return pkt_err(ctx, "Delay too great");
if (o->min_depth > peer->dstate->config.anchor_confirms_max)
return pkt_err(ctx, "min_depth too great");
if (o->commitment_fee < peer->dstate->config.commitment_fee_min)
return pkt_err(ctx, "Commitment fee too low");
if (o->initial_fee_rate < peer->dstate->config.commitment_fee_rate_min)
return pkt_err(ctx, "Commitment fee rate too low");
if (o->anch == OPEN_CHANNEL__ANCHOR_OFFER__WILL_CREATE_ANCHOR)
peer->them.offer_anchor = CMD_OPEN_WITH_ANCHOR;
else if (o->anch == OPEN_CHANNEL__ANCHOR_OFFER__WONT_CREATE_ANCHOR)
Expand All @@ -304,7 +304,7 @@ Pkt *accept_pkt_open(const tal_t *ctx,
if (!proto_to_rel_locktime(o->delay, &peer->them.locktime))
return pkt_err(ctx, "Malformed locktime");
peer->them.mindepth = o->min_depth;
peer->them.commit_fee = o->commitment_fee;
peer->them.commit_fee_rate = o->initial_fee_rate;
if (!proto_to_pubkey(peer->dstate->secpctx,
o->commit_key, &peer->them.commitkey))
return pkt_err(ctx, "Bad commitkey");
Expand All @@ -326,7 +326,6 @@ Pkt *accept_pkt_anchor(const tal_t *ctx,
const Pkt *pkt)
{
const OpenAnchor *a = pkt->open_anchor;
u64 commitfee;

/* They must be offering anchor for us to try accepting */
assert(peer->us.offer_anchor == CMD_OPEN_WITHOUT_ANCHOR);
Expand All @@ -336,15 +335,13 @@ Pkt *accept_pkt_anchor(const tal_t *ctx,
peer->anchor.index = a->output_index;
peer->anchor.satoshis = a->amount;

/* Create funder's cstate, invert to get ours. */
commitfee = commit_fee(peer->them.commit_fee, peer->us.commit_fee);
/* Create our cstate. */
peer->cstate = initial_funding(peer,
peer->us.offer_anchor,
peer->us.offer_anchor == CMD_OPEN_WITH_ANCHOR,
peer->anchor.satoshis,
commitfee);
peer->us.commit_fee_rate);
if (!peer->cstate)
return pkt_err(ctx, "Insufficient funds for fee");
invert_cstate(peer->cstate);

/* Now we can make initial (unsigned!) commit txs. */
make_commit_txs(peer, peer,
Expand Down Expand Up @@ -449,18 +446,14 @@ Pkt *accept_pkt_htlc_add(const tal_t *ctx,
}

cur->cstate = copy_funding(cur, peer->cstate);
if (!funding_delta(peer->anchor.satoshis,
0, cur->stage.add.htlc.msatoshis,
&cur->cstate->b, &cur->cstate->a)) {
if (!funding_b_add_htlc(cur->cstate,
cur->stage.add.htlc.msatoshis,
&cur->stage.add.htlc.expiry,
&cur->stage.add.htlc.rhash)) {
err = pkt_err(ctx, "Cannot afford %"PRIu64" milli-satoshis",
cur->stage.add.htlc.msatoshis);
goto fail;
}
/* Add the htlc to their side of channel. */
funding_add_htlc(&cur->cstate->b,
cur->stage.add.htlc.msatoshis,
&cur->stage.add.htlc.expiry,
&cur->stage.add.htlc.rhash);
peer_add_htlc_expiry(peer, &cur->stage.add.htlc.expiry);

peer_get_revocation_hash(peer, peer->commit_tx_counter+1,
Expand Down Expand Up @@ -498,7 +491,6 @@ Pkt *accept_pkt_htlc_fail(const tal_t *ctx, struct peer *peer, const Pkt *pkt)
Pkt *err;
size_t i;
struct sha256 rhash;
struct channel_htlc *htlc;

proto_to_sha256(f->revocation_hash, &cur->their_revocation_hash);
proto_to_sha256(f->r_hash, &rhash);
Expand All @@ -511,17 +503,10 @@ Pkt *accept_pkt_htlc_fail(const tal_t *ctx, struct peer *peer, const Pkt *pkt)

cur->stage.fail.fail = HTLC_FAIL;
cur->stage.fail.index = i;
htlc = &peer->cstate->a.htlcs[i];

/* Removing it should not fail: we regain HTLC amount */
/* We regain HTLC amount */
cur->cstate = copy_funding(cur, peer->cstate);
if (!funding_delta(peer->anchor.satoshis,
0, -htlc->msatoshis,
&cur->cstate->a, &cur->cstate->b)) {
fatal("Unexpected failure fulfilling HTLC of %"PRIu64
" milli-satoshis", htlc->msatoshis);
}
funding_remove_htlc(&cur->cstate->a, i);
funding_a_fail_htlc(cur->cstate, i);
/* FIXME: Remove timer. */

peer_get_revocation_hash(peer, peer->commit_tx_counter+1,
Expand Down Expand Up @@ -550,7 +535,6 @@ Pkt *accept_pkt_htlc_fulfill(const tal_t *ctx,
Pkt *err;
size_t i;
struct sha256 rhash;
struct channel_htlc *htlc;

cur->stage.fulfill.fulfill = HTLC_FULFILL;
proto_to_sha256(f->r, &cur->stage.fulfill.r);
Expand All @@ -564,19 +548,10 @@ Pkt *accept_pkt_htlc_fulfill(const tal_t *ctx,
}
cur->stage.fulfill.index = i;

htlc = &peer->cstate->a.htlcs[i];

/* Removing it should not fail: they gain HTLC amount */
/* Removing it: they gain HTLC amount */
cur->cstate = copy_funding(cur, peer->cstate);
if (!funding_delta(peer->anchor.satoshis,
-htlc->msatoshis,
-htlc->msatoshis,
&cur->cstate->a, &cur->cstate->b)) {
fatal("Unexpected failure fulfilling HTLC of %"PRIu64
" milli-satoshis", htlc->msatoshis);
}
funding_remove_htlc(&cur->cstate->a, i);

funding_a_fulfill_htlc(cur->cstate, i);

peer_get_revocation_hash(peer, peer->commit_tx_counter+1,
&cur->our_revocation_hash);

Expand Down Expand Up @@ -729,13 +704,16 @@ Pkt *accept_pkt_close_sig(const tal_t *ctx, struct peer *peer, const Pkt *pkt,
struct bitcoin_signature theirsig;

/* BOLT #2:
*
* The sender MUST set `close_fee` lower than or equal to the fee of the
* final commitment transaction, and MUST set `close_fee` to an even
* number of satoshis.
*/
if (c->close_fee & 1 || c->close_fee > peer->them.commit_fee)
if ((c->close_fee & 1)
|| c->close_fee > commit_tx_fee(peer->them.commit,
peer->anchor.satoshis)) {
return pkt_err(ctx, "Invalid close fee");
}

/* FIXME: Don't accept tiny fee at all? */

Expand Down
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